Yeasts

Budding Yeasts

[In "budding"] the parent cell forms a protuberance (bud) on its outer surface; As the bud elongates, the parent cell's nucleus divides, and one nucleus migrates into the bud. Cell wall material is then laid down between the bud and parent cell, and the bud eventually breaks away.

Pseudohypha

Fission Yeasts

Divide evenly to produce two new cells. During fission, the parent cell elongates, its nucleus divides, and two daughter cells are produced. [Increases in the number of yeast cells on a solid medium produce a colony similar to a bacterial colony.

Dimorphism

Spores

Spores are formed from hyphae in a number of different ways, depending on the species. Both sexual and asexual reproduction in fungi occurs by the formation of spores. (Fungi are usually identified by spore type; Fungal spores can survive for extended periods in dry or hot environments. Fungal spores and bacterial endospores are different.)

Asexual Spores

Produced by an individual fungus through mitosis and subsequent cell division. Formed by the hyphae of one organism; When these spores germinate, they become organisms that are genetically identical to the parent.

Sexual Spores

Result from the fusion of nuclei from two opposite strains of the same species of fungus. A fungal sexual spore results form sexual reproduction, which consists of three phases: Plasmogamy, Karyogamy, and Meiosis. (Fungi produce sexual spores less frequently than asexual spores.)

Zygospore

Ascospore

Results from the fusion of the nuclei of two cells that can be either morphologically similar or dissimilar. These spores are produced in a sac-like structure called an ascus. These members of this phylum are called sac fungi because of the ascus.

Basidiospores

(Club fungi; Possess septate hyphae; Include mushrooms.) Formed externally on the base pedestal called a Basidium. There are usually four basidiospores per basidium. Some of the basidiomycota produce asexual conidiospores.

Anamorphs

Mycosis

Any fungal infection [is called mycosis]. Mycoses are generally chronic (long-lasting) infections because fungi grow slowly. Mycoses are classified into five groups according to the degree of tissue involvement and mode of entry into the host: Systemic, Subcutaneous, Cutaneous, Superficial, or Opportunistic.

Systemic Mycoses

Fungal infections deep within the body. They are not restricted to any particular region of the body but can affect a number of tissues and organs. Systemic Mycoses are usually caused by fungi that live in the soil; Inhalation of spores is the route of transmission; these infections typically begin in the lungs and then spread to other body tissues. They are not contagious from animal to human or human to animal. Two systemic mycoses: Histoplasmosis & Coccidioidomycosis.

Subcutaneous Mycoses

Dermatophytes

Fungi that infect only the epidermis, hair, & nails. Their infections are called dermatomycoses, or Subcutaneous Mycoses. Dermatophytes excrete keratinase, an enzyme that degrades keratin (a protein found in hair, skin, & nails. Infection is transmitted from human to human or from animal to human by direct contact. (i.e.- Barber shops have blue anti-bacterial where they soak their tools in order to prevent this kind of fungal infection.)

Superficial Mycoses

Opportunistic Pathogen

Generally harmless in its normal habitat but can become pathogenic in a host who is seriously debilitated or traumatized, who is under treatment with broad-spectrum antibiotics, whose immune system is suppressed, or who has a lung disease. Pneumocystis is an opportunistic pathogen and is the most common life-threatening infection in AIDS patients.

Yeast Infection

Lichen

A combination of a green alga (or a cyanobacterium) and a fungus. Lichens are placed in the Kingdom Fungi and are classified according to the fungal partner, most often an ascomycete (the two exist in a mutualistic relationship-if the partners are separated, the lichen no longer exists). Lichens cans be grouped into three morphologic categories: Crustose Lichens (grow flush or encrusting onto the substratum), Foliose Lichens (more leaflike), and Fruticose Lichens (fingerlike projections).

Cortex

Holdfasts

Stipes

Blades

Algin

A thickener used in many foods (i.e.- ice cream & cake decorations), is extracted from their cell walls. Algin is also used in the production of a wide variety of nonfood goods (i.e.- rubber tires and hand lotion).

Red Tide

Ciguatera

A disease which occurs when the dinoflagellate Gambierdiscus Toxicus passes up the food chain and is concentrated in large fish. Ciguatera is endemic (constantly present) in the south Pacific Ocean and the Caribbean Sea.

Zoospores

Oomycote spores that have two flagella. They were previously classified with fungi (b/c they are superficially similar to fungi) however they are in fact "water molds." Oomycotes are decomposers that form cottony masses on dead algae and animals, usually in fresh water.

Algal Blooms

Trophozoite

Schizogony

Multiple fission; The nucleus undergoes multiple divisions before the cell divides. After many nuclei are formed, a small portion of cytoplasm concentrates around each nucleus, and then the single cell separates into daughter cells. (Protozoa reproduce asexually by fission, budding, or schizogony.)

Amoebazoans

Pseudopods

Apicomplexa

Obligate intracellular parasites that are characterized by the presence of a complex of special organelles at the apexes (tips) of their cells; The organelles in these complexes contain enzymes that penetrate the host's tissue. They have a complex life cycle which involves transmission between several hosts (i.e.- Plasmodium).

Intermediate Host

Tachyzoites

Ciliophora

Ciliates that have cilia similar to but shorter than flagella; The cilia are arranged in precise rows on the cell. They are moved in unison to propel the cell through its environment and to bring food particles to its mouth.

Euglenozoa

Photoautotrophs with a semirigid plasma membrane called a pellicle; Move by means of a flagellum at the anterior end; Also have a red eye spot at the anterior end which senses light and directs the cell.

Slime Molds

Cellular Slime Molds

Typical eukaryotic cells that resemble amoebas; Remain disticint forms their entire life; When their food supply is exhausted they send out chemical signals to others, which soon aggregate into a large sluglike colony that functions as a single organism. It produces a fruiting body which produces spores; It scatters the spores, which can grow into another organism.

Plasmodial Slime Molds

Cytoplasmic Streaming

During cytoplasmic streaming, the protoplasm within the plasmodium moves and changes both its speed and direction so that the oxygen and nutrients are evenly distributed; It continues to grow as long as there is enough food and moisture for it to thrive.

Monoecious/Hermaphroditic

Flatworms

Members of the Phylum Platyhelminthes; Dorsoventrally flattened; Classes of parasitic flatworms include trematodes and cestodes. They cause disease or developmental disturbances in a wide variety of animals.

Flukes

a.k.a. trematodes; Have flat, leaf-shaped bodies with a ventral sucker and an oral sucker, which [together] help to hold the organism in place. They obtain food by absorbing it through their nonliving outer covering, called the cuticle.

Cuticle

Tapeworms

a.k.a. cestodes. Intestinal parasites. Have suckers for attaching to the intestinal mucosa of the definitive host; Some species also have small hooks for attachment. They completely lack a digestive system, so in order to obtain nutrients from the small intestine, they absorb food through their cuticle.

Scolex

Proglottids

Segments produced by the neck region of the scolex, as long as the scolex is attached and alive. Each mature proglottid contains both male and female reproductive organs. The proglottids farthest away from the scolex are the mature ones containing eggs. (Mature proglottids are essentially bags of eggs, each of which is infective to the intermediate host.

Cysticerci

Encysted larvae within muscle meat of the host; When cysticerci are ingested by humans, all but the scolex is digested. (The scolex anchors itself to the small intestine and begins producing proglottids.)

Hydatid Cyst

Roundworms

a.k.a. Nematodes; Members of the Phylum Nematoda; They are cylindrical and are tapered at each end, have complete digestive systems (consisting of a mouth, intestine, and anus), and are dioecious. Males are smaller than females and have one or two hardened spicules on their posterior ends. [Some nematodes are free-living in soil and water, and others are parasites living on plants and animals. Some pass their entire life-cycle, from egg to mature adult, in a single host. 2 types of nematode infections: those which the egg is infective, and those which the larva is infective.]

Vectors

Obligatory Intracellular Parasites

Viruses

Entities that: Contain a single type of nucleic acid (DNA or RNA), Contain a protein coat (sometimes itself enclosed by an envelope of lipids, proteins, and carbohydrates) that surround the nucleic acid, Multiply inside the living cells by using the synthesizing machinery of the cell, Cause the synthesis of specialized structures that can transfer the viral nucleic acid to other cells. Viruses have few or no enzymes of their own for metabolism. To multiply, they must take over the metabolic machinery of the host cell.

Host Range

Bacteriophages/Phages

Virion

A complete, fully developed, infectious viral particle composed of nucleic acid and surrounded by a protein coat that protects it from the environment and is a vehicle of transmission from one host cell to another. Viruses are classified by differences in the structures of these coats.

Continuous Cell Lines

Lytic Cycle

A viral reproductive cycle in which copies of a virus are made within a host cell, which then bursts open, releasing new viruses. Ends with the lysis and death of the host cell. (1. Attachment, 2. Penetration, 3. Biosynthesis, 4. Maturation, 5. Release.)

Phage Lysozyme

Eclipse Period

Lysis

The final stage of viral multiplication is the release of virions from the host cell. The term lysis is used for the Release Stage in the multiplication of T-even phages because in this case the plasma membrane actually breaks open (lysis).

Pinocytosis

Fusion

Alternative method by which enveloped viruses can enter; The viral envelope fuses with the plasma membrane and releases the capsid into the cell's cytoplasm. One example of a virus which penetrates cells using this method is the HIV virus.

Specialized Transduction

Uncoating

The separation of the viral nucleic acid from its protein coat once the virion is enclosed in the vesicle. The capsid is digested when the cell attempts to digest the vesicle's contents, or the non-enveloped capsid may be released into the cytoplasm of the host cell. (This process varies with the type of virus.)

Provirus

Never comes out of the chromosome; Remains in its latent state and replicates when the DNA of the host virus replicates. In other words, the provirus is expressed and produces new viruses which infect adjacent cells.

Transformation

Tumor-Specific Transplantation Antigen (TSA)

Virus-specific antigen on cell surface of many tumor cells. (Tend to be less round than normal cells, and usually exhibit certain chromosomal abnormalities. i.e.- unusual numbers of chromosomes and fragmented chromosomes.)

T Antigen

Antigen in the nucleus of tumor cells. (Tend to be less round than normal cells, and usually exhibit certain chromosomal abnormalities. i.e.- unusual numbers of chromosomes and fragmented chromosomes.)

Latent Infection

Phase in a cycle of an infection after initial onset and the multiplication of pathogens comes to a halt. Pathogen is still there. Common in viruses (Herpes Simplex, HIV, Epstein-Barr), Hepatitis B). NOT the same as remission.

Narrow Spectrum of Microbial Activity

Broad-Spectrum Antibiotics

Superinfection

Infection that occurs while you are being treated for another infection. Growth of a target pathogen that has developed resistance to an antibiotic. (A secondary infection from the removal of normal microbiota, allowing colonizatiion by pathogenic, and often antibiotic resistant microbes.)

Bactericidal

Bacteriostatic

Para-Aminobenzoic Acid (PABA)

The substrate for an enzymatic reaction leading to the synthesis of folic acid, a vitamin that functions as a coenzyme for the synthesis of the purine and pyrimidine bases of nucleic acids and many amino acids.

Penicillin

Refers to a group of over 50 chemically related antibiotics, all of which have a common core structure containing a B-lactam ring called the nucleus. Penicillin molecules are differentiated by the chemical side chains attached to their nuclei. They can be produced either naturally or semisynthetically. They prevent the cross-linking of peptidoglycans, which interferes with the final stages of the construction of the cell walls, primarily gram-positive bacteria.

Natural Penicillins

Penicillin extracted from cultures of the mold Penicillium exists in several closely related forms. These are the so-called natural penicillins. Natural penicillins have some disadvantages. (i.e.- their narrow spectrum of activity and their susceptibility to penicillinases.

Semisynthetic Penicillins

Methicillin-Resistant Staphylococcus Aureus (MRSA)

Resistant to methicillin, penicillin (PCN), etc. Normally found on skin, mucous membranes, in colon and vagina; Infections are in wounds, sputum, UTIs, blood and on skin following tattoo application; Spread by direct contact on the hands of HCWs; May remain on hands for up to 3 hours if not washed, surfaces for days.

Vancomycin-Resistant Enterococci (VRE)

Isoniazid (INH)

Very effective synthetic antimicrobial drug against Mycobacterium Tuberculosis; Primary effect of INH is to inhibit synthesis of mycolic acids, which are components of cell walls only of the mycobacteria.

Ethambutol

Effective only against mycobacteria; Apparently inhibits incorporation of mycolic acid into the cell wall. It is a comparatively weak anti-tubercular drug; It's principal use is as the secondary drug to avoid resistance problems.

Fusion Inhibitors

Disk-Diffusion Method

a.k.a. Kirby-Bauer test; A method used to determine microbial sensitivity to antimicrobial agents in which antibiotic disks are placed on an inoculated Petri dish, incubated, and observed for inhibition of growth.

Erysipelas

Necrotizing Fasciitis

Deep infection of skin that involves destruction of muscle and fat layers, treated aggressively with antibiotics and surgical debridement of infected tissue. (Destroys tissue as rapidly as a surgeon can remove it.)

Pyocyanin

Buruli Ulcer

A disease found primarily in western and central Africa caused by Mycobacterium ulcerans, which is similar to the mycobacteria that causes tuberculosis and leprosy; Progresses slowly with few serious early signs or symptoms. Eventually, the result is a deep ulcer that often becomes massive and seriously damaging.

Commedonal Acne

Inflammatory Acne

Moderate acne arises from bacterial action; At this stage, therapy is usually focused on preventing formation of sebum. Topical agents are not effective, antibiotics are usually prescribed. (It can also be treated with non-prescription treatments that contain benzoyl peroxide.)

Nodular Cystic Acne

Severe acne characterized by nodules, or cysts, which are inflamed lesions filled with pus deep within the skin. These leave prominent scars on the face and upper body, which often leave psychological scars as well.

Smallpox

Monkeypox

First appeared in monkeys, but there are occasional outbreaks among humans; Closely resembles smallpox in symptoms (and was probably mistaken for it) and is known to jump from animals to humans, however transmission from human to human has been limited. Like smallpox, monkeypox is an "arthropoxvirus" and vaccination for smallpox has a protective effect.

Chickenpox

Reye Syndrome

An occasional severe complication of chickenpox, influenza, and some other viral diseases. A few days after the initial infection has receded, the patient persistently vomits and exhibits signs of brain dysfunction, such as extreme drowsiness or combative behavior; Coma and death may follow.

Shingles

Vesicles, similar to those of chickenpox, occur but are localized in distinctive areas (typically about the waist); Limited to one side of the body at a time. The patient has partial-immunity to the virus.

Breakthrough Varicella

Varicella in previously vaccinated persons; A relatively mild disease with a rash (which does not look like typical varicella); A booster dose of the vaccine may eventually be needed for complete control of varicella.

Congenital Rubella Syndrome

Fifth Disease/Erythema Infectiosum

Produces no symptoms at all in approx. 20% of infected individuals; Symptoms are similar to a mild case of influenza, but there is a distinctive facial rash that slowly fades; May cause anemia, an episode of arthritis, or, rarely, miscarriage, in adults.

Tinea Pedis

Tinea Unguium

Candidiasis

Thrush

Scabies

Disease which involves intense local itching and is caused by the tiny mite Sarcoptes scabiei burrowing under the skin to lay its eggs. The burrows are often visible as slightly elevated lines. Scabies may also appear as a variety of inflammatory skin lesions, many of them secondary infections from scratching. Transmitted by intimate contact.

Ophthalmia Neonatorum

Inclusion Conjunctivitis

a.k.a. Chlamydial Conjunctivitis; Quite common today, it is caused by a bacterium that grows only as an obligate intracellular parasite. Tends to spread in unchlorinated waters of swimming pools as well as from mother to child during childbirth.

Trachoma

A serious eye infection, and probably the greatest single cause of blindness by an infectious disease; Caused by certain serotypes of Chlamydia trachomatis but not the same ones that cause genital infections.

Herpetic Keratitis

Caused by the same herpes simplex type 1 (HSV-1) that causes cold sores and is latent in the trigeminal nerves. The disease is an infection of the cornea, often resulting in deep ulcers, that may be the most common cause of infectious blindness in the U.S.

Acanthamoeba Keratitis

This amoeba is found in fresh water, hot tubs, tap water, and soil; most cases have been associated with wearing contact lenses. Contributing factors include inadequate, unsanitary, or poor disinfecting procedures.